7,498 research outputs found
Equiangular subspaces in Euclidean spaces
A set of lines through the origin is called equiangular if every pair of
lines defines the same angle, and the maximum size of an equiangular set of
lines in was studied extensively for the last 70 years. In this
paper, we study analogous questions for -dimensional subspaces. We discuss
natural ways of defining the angle between -dimensional subspaces and
correspondingly study the maximum size of an equiangular set of -dimensional
subspaces in . Our bounds extend and improve a result of
Blokhuis
A hem érfal komponensekre kifejtett közvetlen és közvetett patofiziológiai hatásai = Pathologic effects of heme on components of vessel wall via direct and indirect mechanisms
Kimutattuk, hogy az atheroma lipid magja prooxidáns környezetet teremt, ahol a vörösvértestek szétesnek, a hemoglobin ferri- és ferrylhemoglobinná oxidálódik, és a felszabaduló hem és vas lipidoxidációt indít el. Leírtuk, hogy a hemoglobin oxidáció (ferrylhemoglobin keletkezése) a vascularis endothelium aktiválása révén kifejezett proinflammatorikus hatással rendelkezik. Demonstráltuk, hogy a hemoxigenáz-1 (Hmox1 gén) megelőzi a malária központi idegrendszeri szövődményeit kísérleti állatmodellben. A jótékony hatásokat a szénmonoxid hemoglobinhoz történő kötődése okozta, megakadályozva a hemoglobin oxidációt és a hem disszociációját, ami az idegrendszeri szövődmények kialakulásáért felelős. Kutatásaink felvetik annak a lehetőségét, hogy a nemespenésszel érlelt élelmiszerek, nevezetesen a sajttermékek, és a sziderofórokat tartalmazó funkcionális élelmiszerek beiktatása a diétában csökkentik a szív és érrendszeri megbetegedések előfordulását. Felfetük, hogy a hemoxigenáz-1/ferritin rendszer aktivitása hatékonyan gátolja a kalcifikációt és a simaizomsejtek csontsejt irányú transzformációját, és a hatást elsősorban a ferritin nehéz láncának ferroxidáz aktivitása közvetíti, másodsorban a biliverdinnek köszönhető. Továbbá, eredményeik bizonyítékot szolgáltat arra vonatkozóan, hogy a hem-stressz gátolja a csont mineralizációt, és ez a hemoxigenáz-1/ferritin aktivációnak köszönhető, közelebbről a forroxidáz aktivitásnak. | We demonstrated that interior of advanced atheromatous lesions is a pro-oxidant environment in which erythrocytes are lysed, hemoglobin is readily oxidized to ferri- and ferrylhemoglobin, and released heme and iron promote further oxidation of lipids. We revealed that oxidized hemoglobin, i.e. ferrylhemoglobin, acts as a proinflammatory agonist that targets vascular endothelial cells. We reported that heme oxygenase-1 (encoded by Hmox1) prevents the development of experimental cerebral malaria. These effects were mediated by the binding of carbon monoxide to hemoglobin, preventing hemoglobin oxidation and the generation of free heme, a molecule that triggers cerebral malaria pathogenesis. The consumption of mold-ripened food products such as aged cheeses and the introduction of functional foods and food additives rich in fungal iron chelators in diets may lower the risk of cardiovascular diseases. We conclude that induction of the heme oxygenase-1/ferritin system in response to heme prevents phosphate -mediated calcification and osteoblastic differentiation of human smooth muscle cells mainly via the ferroxidase activity of ferritin. Our studies provided evidence that heme decreases mineralization and demonstrates that this suppression is provided by heme-induced upregulation of ferritin. In addition, we conclude that inhibition of osteoblast activity, mineralization, and specific gene expression is attributed to the ferroxidase activity of ferritin
Dynamic provisioning: a countercyclical tool for loan loss reserves
In the wake of the financial crisis of 2007-2009, as various banking policymakers revisit loan loss provisioning rules, the Spanish approach of dynamic provisioning has garnered attention as a potential alternative to the current incurred loss approach. We review the current approach to loan loss reserves in the United States, focusing on how loan loss reserves relate to bank solvency and why the current accounting approach may have procyclical effects. We present a conceptual framework to compare loan loss provisioning under the incurred loss framework and dynamic provisioning. Then we simulate dynamic provisioning with U.S. data to present an empirical comparison.Loans
Orthonormal representations of -free graphs
Let be unit vectors such that among any
three there is an orthogonal pair. How large can be as a function of ,
and how large can the length of be? The answers to these
two celebrated questions, asked by Erd\H{o}s and Lov\'{a}sz, are closely
related to orthonormal representations of triangle-free graphs, in particular
to their Lov\'{a}sz -function and minimum semidefinite rank. In this
paper, we study these parameters for general -free graphs. In particular, we
show that for certain bipartite graphs , there is a connection between the
Tur\'{a}n number of and the maximum of over all -free graphs .Comment: 16 page
Privatization, Unemployment and Subsidy
transition, privatization, unemployment
Simulations of a weakly conducting droplet under the influence of an alternating electric field
We investigate the electrohydrodynamics of an initially spherical droplet
under the influence of an external alternating electric field by conducting
axisymmetric numerical simulations using a charge-conservative volume-of-fluid
based finite volume flow solver. The mean amplitude of shape oscillations of a
droplet subjected to an alternating electric field for leaky dielectric fluids
is the same as the steady-state deformation under an equivalent root mean
squared direct electric field for all possible electrical conductivity ratio
and permittivity ratio of the droplet to the surrounding fluid.
In contrast, our simulations for weakly conducting media show that this
equivalence between alternating and direct electric fields does not hold for
. Moreover, for a range of parameters, the deformation obtained
using the alternating and direct electric fields is qualitatively different,
i.e. for low and high , the droplet becomes prolate under alternating
electric field but deforms to an oblate shape in the case of the equivalent
direct electric field. A parametric study is conducted by varying the time
period of the applied alternating electric field, the permittivity and the
electrical conductivity ratios. It is observed that while increasing has
a negligible effect on the deformation dynamics of the droplet for , it
enhances the deformation of the droplet when for both alternating and
direct electric fields. We believe that our results may be of immense
consequence in explaining the morphological evolution of droplets in a plethora
of scenarios ranging from nature to biology.Comment: 10 pages, 8 figure
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